The invention pertains to eccentricity compensating seals interposed between shafts and planar sealing surfaces such as a gland surface.
Fluid type seals capable of compensating for slight eccentricites between a shaft and a gland member are known wherein sufficient clearances exist to permit relative radial displacement between the seal and its associated members. Also, it is known to use spring biasing means to augment the resilient characteristics of the seal, as shown in U.S. Pat. No. 2,193,326, and synthetic plastic seals have been constructed of materials having excellent wear-resisting qualities, as well as a resistance to corrosion, and such seals have been known to utilize lips or flanges to augment sealing, as shown in U.S. Pat. Nos. 2,998,987 and 3,380,745.
While a wide variety of seal constructions provide effective sealing between a shaft and associated member, with either respective rotating or reciprocating motions, known seal constructions wherein significant eccentricity exists during shaft movement, either rotary or linear, often are not capable of maintaining effective sealing over extended durations.
The presence of eccentric shaft movement causes relative movement between the seal surfaces and the surfaces engaged thereby, causing wear on the seal surfaces which, eventually, destroys effective sealing. Also, resilient forces imposed upon the seal to maintain engagement between relatively moving components often vary if such forces are produced by the resilient nature of the seal material.
Further, with a linearly displaceable shaft the axial forces imposed upon the restrained seal mechanism produce wear in the seal and it is difficult to maintain an effective sealing seal efficiency over extended periods of time.